Vibrational Feshbach resonances in electron attachment to nitrous oxide clusters: decay into heterogeneous and homogeneous cluster anions

Using a high-resolution (ΔE≈1 meV) laser photoelectron attachment method, we have studied cluster anion formation in collisions of low-energy electrons (1–180 meV) with (N2O)N clusters. We show that formation of both heterogeneous cluster anions (N2O)qO− (q<N) and (as a minor channel) of homogeneous anions (N2O)p− (p⩽N) is mediated through narrow, weakly red-shifted vibrational Feshbach resonances of the type [(N2O)N−1·N2O(νi)]− (νi denotes vibrational excitation). For the first time direct information has been obtained on the relationship between the size q of the heterogenous anions and the size p of the homogeneous anions (p–q≈2–3 for p=8, 9, 11, 13), as formed from the same precursor cluster size involved in the vibrational Feshbach resonance. The electron-cluster binding energies are recovered from model calculations based on appropriate short- and long-range forces.